Over 198,100 men will be diagnosed with prostate cancer each year. Typically, forty percent will choose interstitial implant therapy, one-third of the men will choose surgery, and one third will choose external beam radiotherapy.
Typical treatments for prostate cancer include surgical removal of the prostate (prostatectomy), freezing the prostate (cryosurgery), hormonal therapy, prostate seed implant therapy, or prostate conformal radiation.
The treatment providing the best outcome is still debatable. However, the side effects of treating prostate cancer have become less toxic and less profound with implant therapy and 3D conformal radiotherapy. Advancements in treatment positioning and target localization have significantly improved outcomes and diminished the side effects.
Since the conception of 3D conformal radiotherapy, physicians have paid attention to the delivered dose to the target and surrounding tissues. Investigators have been able to correlate side effects to the amount of tissue receiving a certain radiation dose. This term has been coined: dose volume histogram. For conformal radiotherapy it is conventionally preferred that the rectum receive less than 40% of the prescribed treatment dose in hopes of minimizing the radiation induced side effects.
Time, distance, and shielding affect the dose that is delivered. The less time an area is exposed to radiation, the less dose delivered. The greater the distance from the radiation, the less dose delivered. Finally, more shielding will also decrease the delivered dose.